Narcosis apparatus



May 27, 1969 J. HAUPT 3,446,243

NARCOS IS APPARATUS Filed Dec. 12, 1966 INVENTOR Jasef flea 0f M My ATTORNEYS United States Patent 1) 49,09 Int. Cl. B01f 3/02,- A61m 17/00 US. Cl. 137599.1 1 Claim ABSTRACT OF THE DISCLOSURE A plurality of tubes connected in parallel is used as a throttle in the by-pass line of a vaporizer.

This invention relates to an apparatus such as disclosed in U.S. Patent to Schreiber et al., No. 3,107,689, in which an anesthesia or narcosis apparatus has a pipe by-passing the atomizer with control valves in the by-pass pipe and the atomizer lines. These valves are adjustable throttle valves, one of which is inserted in the by-pass pipe and one in the atomizer line. Each valve is of the same size and has a length to width valve opening ratio of less than l0 The valve arrangement has the advantage in that the ratio of the mixture of intake gas and atomized gas remains substantially constant regardless of the change of gas velocity in either the vaporizer or the bypass pipe. This practically produces a laminar gas flow. The resistance characteristics of the throttles is approximately linear. On the other hand, any desired mixture of intake gas with atomized gas can be obtained by adjusting the throttle valves. The throttle valves are conical valves with a conical valve head and a complementary valve seat.

The improvement of this invention is used especially when the patient is forced to inhale the gas mixture from the atomizer by using his thorax muscles. In this invention, the throttle means in the by-pass pipe is composed of a plurality of tubes connected in parallel with the ratio of the interior diameter of each tube to the length of the tube being less than 1:50. This invention has the advantage that the resistance to the flow of gas in the by-pass pipe can be adjusted so low that the patient is able to inhale the gas from the atomizer by using his thorax muscles and without difl'iculty.

The two gas passageways principle is used in the construction of the atomizer of this invention. A portion of the intake gas is moved through the atomizer on a first passageway. In the vaporizer discharge pipe is a throttle means composed of a valve having a conical valve head and a complementary valve seat. The head is adjustable so that the ratio of the width of the space between the valve head and valve seat to the length of the valve is less than 1:50. This results in a substantially laminar flow of gas through this valve. The resistance characteristics are almost linear. In the second passageway, a considerably larger portion of the gas by-passes the atomizer chamber. The throttle means in this second passageway in this invention is composed of a plurality of tubes in which the ratio of the interior diameter to the length of each tube is always less than 1:50. The resistance characteristics of this bundle of tubes is almost linear. The combination of the conical valve with the bundle of tubes results in that the distribution ratio of the gas during a change in the gas flow volume remains constant because each throttle means has substantially identical linear characteristics.

The means by which the objects of the invention are obtained as described more fully with reference to the accompanying schematic drawing showing a cross-sectional view through the apparatus.

Gas, such as air or mixtures of oxygen, laughing gas, or the like, enters intake pipe 1 and flows to the distributor chamber 2 of the atomizer. A portion of the gas flows through the inlet pipe 3 into the vaporizer 4 and out of the vaporizer through the vaporizer discharge pipe 5 in which is mounted a conical throttle valve 6 which has the opening width to length ratio heretofore described. The gas then flows in pipe 5 to a mixing chamber 7 and out of the vaporizer through the outlet pipe 8 to the lungs of the patient.

Starting from pipe 1, a by-pass pipe 9 is joined with outlet pipe 8 at the mixing chamber 7. Inserted in the bypass 9 is a bundle of tubes composed of a plurality of tubes connected in parallel to form a throttle means and with each tube having an interior diameter to length ratio less than 1:50. This corresponds to the valve opening to valve length ratio of conical valve 6 which is less than 1:50.

It is thus seen that the gas flowing through the first passageway containing the adjustable valve 6 is mixed with a substantially larger portion of the gas flowing through the second passageway containing the tube bundle 10. Both streams of gas are then intimately mixed and fiow to the patient.

The tube bundle 10 and the valve 6 both have linear resistance characteristics. Consequently, when the volume of flow through the apparatus is changed, there is no change in the ratio expressed in percentages between the two gas flows. This has the advantage in that no change in the concentration of the narcosis or anesthesia gas takes place even though there may be a change in the velocity of gas flow because of the differences in less than atmospheric pressure produced by the thorax muscles of the patient. Also, the concentration of the vaporized gas can be adjusted by means of the valve 6 to any desired value.

Having now described the means by which the objects of the invention are obtained,

I claim:

1. In a narcosis apparatus having a gas inlet pipe, 21 gas outlet pipe, a vaporizer by-pass pipe extending between said inlet and outlet pipes, at vaporizer discharge pipe connected between said vaporizer and said outlet pipe, and throttle means in each of said by-pass pipe and said discharge pipe, respectively, the improvement in which the throttle means in said by-pass pipe comprises a plurality of tubes connected in parallel with linear resistance characteristics, and each tube having a diameter to length ratio of less than 1:50.

References Cited UNITED STATES PATENTS 3,107,689 10/1963 Schreiber et al. 137599.1 3,257,911 6/1966 Garnjost et al 13784 X LEONARD D. CHRISTIAN, Primary Examiner.

US. Cl. X.R. 138-37 

